1. Field of the Invention
The present invention relates to a case for accommodating a disc-shaped recording medium, such as a compact disc (CD), digital video disc (DVD) and the like, on which music or an image is recorded.
2. Description of the Related Art
One of conventional cases for carrying a disc-shaped recording medium includes holding means with a central portion which is depressed by a finger such that its diameter is reduced, thereby releasing the recording medium from a held state. For example, Japanese Patent No. 2863317 discloses a compact disc holder including an integrally formed button member having a generally semicircular segment connected via a central hinge to distal ends of two cantilevered arms extending inward from the disc base. A central aperture of the compact is to be fitted with the segment. The central aperture of the disc is placed on the button member and then, the disc is depressed to be fixed and held. On the other hand, when the central portion of the button member is depressed while the disc is held, the arms are flexed to be pushed toward the disc base such that a lip of the button member passes through the central aperture. As a result, the disc is released from engagement with the button member. However, when an unexpectedly large external force acts on the case during handling or transportation, the central portion of the case is sometimes pressed. In this case, the disc held on the button member is detached, whereupon the surface of the disc may be damaged.
In view of the above-described problem, JP-A-2001-206478 discloses an improved disc case. The disclosed case includes a holder including a protrusion limiting the position of the central aperture of the disc and an engagement portion having an engagement portion elastically fitted with an inner wall of the central aperture of the disc limited by the protrusion. The engagement portion includes a cantilevered arm with a distal end on which the button is mounted. The button is depressed to a position immediately before release from the engagement with the disc. The height of the protrusion is set to be substantially the same as the height of the button located at the position immediately before release from the engagement with the disc. As the result of this set height of the protrusion, the button can be prevented from being released from engagement with the disc.
JP-A-2003-26271 filed by the assignee of the present application discloses a case for accommodating a disc-shaped recording medium including a protrusion mounted on the backside of a door. The upper side of the recording medium is pressed directly or indirectly by the protrusion. A lowering operation of the pressing portion of the holder is equalized with a spring of a thrust portion so that the recording medium is prevented from falling off.
Regarding the holder disclosed by the foregoing Japanese Patent No. 2863317, the recording medium would become defective if the surface of the recording medium is damaged during transportation or the like. Further, in the holder disclosed in JP-A-2001-206478, the button-shaped lip engages one inner portion of the central aperture of the disc to hold the disc. Accordingly, the disc is not sufficiently stable when held by the holder. The structure of the case disclosed in JP-A-2003-26271 can prevent the disc from dropping off. However, since the protrusion presses a pamphlet put inside the door, the pamphlet sometimes carries an indication of press.